854 DR. G. J. HINDE ON RECEPTACULITIDA, 
VI. GENERA NOT BELONGING TO THE GROUP, BUT USUALLY 
INCLUDED THEREIN. 
A notice of the family would be incomplete without referring to 
certain other genera which have been, by various paleontologists, 
included in it, and indicating the reasons for their omission. Be- 
ginning first with Hichwald*, we find that, in addition to the genera 
herein recognized as proper to the family, he has included two others, 
Mastopora and Escharipora, Hall. The former genus is undoubtedly 
congeneric, if not identical, with Midulites fuvus, Salt., and will 
presently be mentioned in connexion with Oyclocrimus; the latter 
name is applied by Hall to a Polyzoon, but the form which Eich- 
wald regarded as identical with Hall’s type species has certainly no 
relation to it, nor to the Receptaculitide, though I am unable to 
judge from the figure and description to what group it may be- 
long. 
F, Romer? has embraced in the Receptaculitide, besides the re- 
cognized genera, the following : Cyclocerinus, Kichwald (= Nidulites, 
Salt.), Pasceolus, Bill., and Archwocyathus, Bill., though he acknow- 
ledges that these forms stand in very various degrees of relationship 
to the typical genera of the group. To these Zittelt has further 
added Goniolina, D’Orb., Archcocyathellus, Ford, and Protocyathus, 
Ford. 
From an examination of specimens of Cyclocrinus Spasku, Kichw., 
from the Silurian at Anticosti, and of Nidulites favus, Salt., from 
Lower Llandovery strata at Haverfordwest, and from Mullock Hill, 
Ayrshire, I am unable to see any structural resemblance in them to 
any of the Receptaculitide. The type of Cyclocrinus is a spherical 
body whose outer surface is covered with regularly arranged cup-like 
depressions, rounded below, with a small central circular aperture 
which opens into the central hollow body-cavity, and with penta- 
gonal or hexagonal margins. Fitting into these small cup-like 
depressions are short, hollow, prismatic cells with rounded bases, 
which, like the cups, are perforated. I have not seen in the cups 
any traces of the short rays figured by Hichwald §; their absence, 
‘however, may be owing to the fossilization of the specimens. There 
is no feature in these fossils analogous to the spicules of the Recep- 
taculitide ; the structures which F. Romer compares to the vertical 
spicular rays in Ischadites appear to me to be prismatic cells, or 
short tubes with open surface-apertures. Though convinced that 
Cyclocrinus and its equivalent, Nidulites, have no connexion with 
Ischadites and its allies, 1 am not prepared to offer any suggestion 
as to their real characters. 
The genus Pasceolus||, Billings, is just as enigmatical as Cyclo- 
crinus. It has been compared with Spherospongia, Pengelly ; but 
* Lethea Rossica, vol. i. pp. 434, 495. t Lethza Pal. Th. i. p. 286. 
+ Handb. der Pal, vol. i. p. 728. 
§ Leth. Rossica, vol. i. p. 688, Atlas, t. 32. f. 21 0. 
|| Can. Geol. Surv. Rept. 1856, p. 842; Pal. Foss. Can. vol. i. p. 390, f. 366; 
Cat. Silur. Foss, Anticosti, p. 69. 
